Circuit interrupting apparatus



June 26, 1945. A. TRIPLETT CIRGUIT INTERRUPTING APPARATUS Filed Nov. 12, 1940 5 Sheets-Sheet 3 June 26, 1945. TRIPLETT 2,379200 G IRCUIT INTERRUPTING .APPARATUS f'zzren or: Ez q/2 %Tri vle# June 26, 1945.

H. A. TRIPLETT CIRCUIT INTERRUPTING APPARATUS 5 she'ets-sheet 5 Filed Nov. 12, 1940 which:

Patented June 26, 1945 ClRGUIT INTERRUPTING APPAEATUS 4 Hugh A. T-lplett, Wilmette, lil., 8583811031 to Schweitzer .e Conrad Inc., Chicago, m., corporatlon of Delawue y u Application November 12, 1940, Serial No. !85,232- 25 Claimsu (Ci. zoo-417 This invention rela/ces, generally, to circuit interrupting appai'atus, and it has particular relaton to ruse devicesior interrupting relatively high alternating Currents at relatively high voltages, such as 5000 to 10,000 amperes at 115,()00 volts.

An object oi this invention is to automatically vent a metallic condenser chamber of a fuse of the blast action type on generation of predetermined pressure therein. v

Another object of this invention isto clamp a renewable fuse cartridge in place through the condenser. v e

A further' object of this invention 'is to spirally wrap one or more metallic sheets in'spaced relation to provide a large area for cooling and condensing the discharge from a fuse of the biast action type.

It is another object of this 'nvention to provide for indicating that a solid material fuse has opc-rated.

Still another object of this invention is to securely clamp the Cartridge termineis of e. solid material fuseto the line terminals of a fuee housing. y

It is also an object oi this invention to prevent distortion of the fiexible conductor which is looped over the pulley' of th Operating mechanisi-n for a solid material *ruse and. which interconnects the movable terminal with the edjacent Cartridge terminal on operation of the ruse,

uti'other object of this invention is to so proportioh the refill unit that following e eii'ouit interrupting operation the voltage required to eshover the gap within the unit is less than'that required to fiashover the exterior thereot or to set np an are between, the ferrules of the ruse housing. g

Other objects of this invention will, in part. he obvious and in part appear hereinafter.,

For a more complete Understanding oi the nature andscope of this invention, reference may he had to the following detailed description, taken together With the accompanying drawings in Figur-es 1 and 2, taken together, comprise a lonv gitudinal sectional view of a blast action type of hise constructed in accordance with the present invention, the -replaceable cartridge" being shown in elevation;

i Figures 3 and 4, taken together, comprise a longitudinal sectional View of the replaceable fuse eartridge: i u Figura 5 is a top plan view of the condenser assembly shown in Figura 1; r i

longitudinal sectional view of another -embodiment of the invention; and

Figure 10 is a longitudinal sectional view of the refill unit or replaceable cartridge in the blown condition. e

Referring now particularly to Figures 1 and 2 of the drawings, it will be observed that the reference character n designates, generally, a tubular fuse housing that is fonned by a sleve or tube ll of suitable insulating material, such as glass or porcelain, which hascorrugations |2 ad :lacen't its upper end for increasing the leakage surface after the device has operated; The tube or sieeve I l is provided with upper and lower ringlike line terminals !ti and, N which are Secured in place prefembiy by means of alloy seals. The line ter-iniziale is end it ere slotted as indicateci et li and i& to permit the use of a relavely high mitim: point ailoy i'oz` forming the seal as deeci'ibed in McMahon et el. Patent No. 2,20'i',tl3. The rapper line terminal it is provided with e fienge il against whieh heecled portion i@ oi a. cortridee terminal ta ot the upper end of e cartridge housing: 26 oi' e replaceeble certridge, shown generolly et 22, reacte. At its lower end the certridge i@ is provided with fiemble conductoi'e 23 which external out of the lower end of the tube or eleeve -i i and are passed through Slots 24 in the lower line terminal it where they ere clamped eecurely thereto by e, cletmp nut 25.

The lower line terminal lt is provided. with e raolieily inweroiiy attending. flonge 29 against which reects en outted flenge :iii of a metellic contact sleeve ti which. ae showh, extends inwardly of the tube or eleeve ii from the lower line terminal i@ toward me upper line terminal 63. The contact sleeve 35 is eiamped in place by a, metsillic guide sleeve 32 which, as illustrated, is threaded into the lower line terminal !4. The guide sleeve 32 is provided at its lower end with a rediaiiy inwardly extending flange. 33 which forms a step. as will be presently set forth.

At its upper end the contact sieeve -3l is slotted longitudinally to provide flexible contact fingers 34 which are bent inwardly intermediate their ende for contact engagement with the expanded upper end 35 ot a metallic aleeve 36 which is telescoped onto the lower end of the .cartridge housing !I and forms &second cartridge terminal. As

.will-hereinatter appear, when the circuit interrupter' ope'atesgthefm etallic sleeve or cartridge terminal 28 moves downwardly until its lower end engages the flange 33 oi the guide sleeve 32. At

the same time the flexible conductors 23 are moved downwardly out oi' the lower end ol the tube or sleeve I I, and, by their changed position, indicate that the device has operated.

The upper line terminal !3 is provided with an integrelly formed extension 39 to provide a metallic condenser chamber in which a condenser, shown generalhr at 40, is positioned :or cooling and condensing the blast discharged rrom the cartridge 22 when it operates. As shown more clearly in Figure oi the drawings, the condenser 40 comprises a corrugated strip 41 of metal, such as copper. and a fiat spacer strip 42, also of metal, such as copper. The strips 41 and 42 are spirally wound and placed inside of a cylindrical metallic sleeve 43. The strips 4I and 42 are wound to gether on an arber, the corrugated strip 41 serving to space the turns of the fiat strip 42 uni- Iormly apart. As shown in Figure l, the turns ot the spirally arranged strips 4! and 42 are located substantially parallel to the direction of the blast from the cartridge 22.` The metallic strips 4| and 42 are held in place in the sleeve 43 by metallic spiders 44 and 45 which are Secured to the sleeve 43 by suitable means such as screws 48.

As shown in Figure 1 oi! the drawings, the upper end or the condenser chamber 39 is closed by a cap 41 which is threaded into the upper end of the same. Openings 48 are provided in the cap 41 to permit discharge of the blast to the atmosphere. A valve 49. which is carried by a valve stern 50 slidably mounted in the cap 41, serves to close the openings 49. The valve stem u carries at its lower end a valve spring seat !ii against which a. coil compression spring 52 reacts i'or holding the valve 49 closed. `It will be understood that, upon the generation o! a predetermined pressure within the condenser chamber 29, the valve 49 will be liited automatically to permit discharge of the blast products to the atmosphere. On reduction oi the pressure, the valve 49 will be automatically closed.

The details o! construction of the replaceable !use cartridge 22 are shown in Figures 3 and 4 of the drawings. It will be noted that the cartridge housing 2! comprises an outer sleeve 55 ot insulating material, such as a phenolic condensation product, and an inner insulating sleeve !E formed preierably of fiber. housing 2l there is provided a filling of solid arc extinguishing material in the form of rings 51 of boric acid, for example. The rings 51 form a bore u through which a red-like terminal !9 is adapted to be drawn on operation of the device. The upper end of the bore 59 formedby the rings 51 oLsolid arc extlnguishing material is flared outwardly as indicated at il, The rings are held 'in place at the upper end by a retaining plug Bl o! insulating material, such as fiber, the inner surface ot which is flared' outwardly as shown. At the lower end of the rings 51 of solid arc !extinguishing material there is provided a plug 92 of insulating material, such as fiber, which is threaded into the lower end ot the flber'inner sleeve 54'. A pin u of insulating material, such as a phenolic condensation product, projects through' the inner fiber sleeve into the plug 62 for holding the latter in place.

The rod -liketerminal 59 is connected by means of a Iusible element 44, preierably formed of silver,.to a contact plug 85 which projects through and is Secured to the upper cartridge te-inal ll.

within the cartridge 2,37a2oo chromum alloy wire, interconn'ects the rod like e terminal 59 and a stran pin 51 which extends transversely of the upper cartridge terminal !9. as shown. e

The lower end of the red-like terminal 59 is threaded into the upper end of an adapter 68 and is Secured therein by a transverse pin 59. It will be noted that the flexible conductors 23 extend up into the adapter 68, and that it is deformed thereon as indicated at n to provide good electrical and mechanical connection thereto. Integrally formed with the adapter sa is a threaded plug 'll which is screwed into the lower end of the metallic sleeve or cartridge terminal 35. A pin 12 serves to prevent rotation of the plug 'll with respect to the sleeve 35.

The metallic sleeve 36 serves not only as a car tridge terminal, but also it serves to house a coil compression spring 13 which is arranged to react between the lower end of the Cartridge housing 2l and the upper surface of the plug 'I i. It will be understood that the spring 13 'will be restrained as long as the usihle and strain elements 54 and 66 remain intact. On blowing of these elements, the rod-1ike terminal 59 will no longer be restrained and it will move downwardly through the bore 58, drawing the arc for-med between its upper end and the upper cartridge terminal !9 into the same-where the heat thereof 'evolves an arc extinguishin medium from the bore 58 which assists in extinguishin'g the arc thus drawn. The red-like terminal 59 is fastened" to the metallic sleeve 39 so that the two move together downwardiy under the influence of the spring 13.

The expanded portion 35 of the metallic sleeve H that is telescoped with t e lower end oi the cartridge housing 2| is provided with a short longitudlnally extending slot 14 that inter-tits with a pin 15 extending through th cartridge housing 2l. The pin 15, which is preferably for-med of insulatng material, such as a phenolic condensation product, prevents relative rotation of the Cartridge housing 2l and the metallic sleeve 36 as long as th fusible and strain elements 84 and 66 remain intact. The slot 14 permits the metallic sleeve 36 to move out of engage ment with the pin 15 when these elements have blown.

In Figures 8 and 9 of the drawings there is shown another embodiment of the invention. A tubular housing, shown generally at is pro- Vided which comprises a tube or sleeve ai for-med of glass or porcelain and having corrugations 42 adjacent its upper end. Upper and lower generally ring-like line terminals 83 and 84 are provided at the ends of the tube or sleeve il, and they are slotted as indicated at 85 and ll for the purpose previously described.

The upper line terminal 83 is provided with a radially inwardly extending flange I'l against which reacts a head portion sa oi a cartridge i terminal 89 that is Secured to the upper end of a Cartridge housing 9| which forms a part of a re- 'placeable cartridge that is designated generally 2,37aaoo such as fiber. within the cartridge housing 9! there is provided solid are cxtinguishing material in the form of rings 95 which are stacked one above the other and provide a bore 96 extendin'g longitudinally therethrough. The bore 96 is ar- I ranged to receive a red-like terminal 91 which is' movabe therethrough. The upper end of the bore 96 is flared outwardly as indicated at 98. A retaining ring 99, preferably formed of fiber, with 'its inner surface flared outwardly, serves to hold tridge terminal 39. A strain element &02, preferabiy formed of :nickel chromium aiioy wire, interconnects the rod-like terminal 91 and a strain pin !93 which extends transverseiy of the upper cartridge terminal 39, for relieving the fusible element of Stress tending to move the red-like terminal 91.

The upper line terminal is provided with an integrally formed extension !03 that forms a metallic expansion chamher for the products of the blast generated on blowing of the iusible and strain elements !00 and !02. within the expansion chamber formed by the extension !06 there is provided a condenser assembly which is generally similar to the condenser assembly 40 shown in Figures 1 and oi' the drawings and previously described. Acap 103 closes the upper end of the extension os and'is provided with openings !09 i for venting the interior. A valve !!0 serves to close the openings !09. The valve !!0 is carried by a valve stern !!l that is slidably mounted in the cap !03. v At its lower end the valve stem is provided with a valve spring seat !!2 against which a coil compression spring !!3 reacts. on

the generation of a predetermined pressure within the expansion chamber !06, the spring !!3 is compressed *and the valve 'I o is lifted. The

pressure is relieved through the openings !09 after whiclrthe valve= !!0 isautomatically closed by the spring !!3. V

`At`its lower end the Cartridge housing 9! has secured thereto a. metallic sleeve !!3 ,which forms part of a second cartridge terminal. A pin .!!1

serves topi-event relative rotation between the metallic sleeve !!3 and the Cartridge housing 9!. At its lower end the metallic sleeve P!! has threaded therein 'a metallic ferrule !!3, thereby rforming an extension thereoi, which projects a the for interconnecting the lower line terminal 84 'and the lower cartridge terminal !!6 and the ferruie !!3 in such manner *as to accommodate any relative positions likely to be encountered. For this purpose contact fingers !!9, integrally cuter surface of the ferrule na so that accurate longitudinal .alignment therebetween is not reqired. The lo'wer ends of the contact fingers !!9 are beveled as indicated at !22 for receiving a. correspondingly shaped surface of a clamp nut !23 that is threaded onto the lower end of the lower line terminal 94. rw'hen 'the clamp nut !23 is tightened, the contact flngers l !9 are urged. inwardly into g'ood contact engagement with the ferr-ule !!8. The construction of the line termi nal 84 together with the contact fingers !!9 and the clamp nut !23 is generally similar to the clamp construction shown in McMahon et al. Patent No. 2,183,'151.

Slidably mounted within the metallic sleeve !!9 is an indicator tube !25 that maybe formed of metal; The indicator tube !25 carries a base 523.

at its lower end to which a generally U-shaped pulley bracket !21 is secured by mears of a bolt !23 that is held in place by a nut !29. A looking screw serves to hold the nut !29 in place. A pulley sha ft l3! extends between the arms of the bracket !21, and a pulley !32 is rotatably mounted thereon. i i

Looped over the pulley !32 is a fiexible conductor or cable !33 which is provided with a sheath !34 in the form of a closely wound coil spring that is .preferably formed of stainless steel. The sheath !34 protects the fiexible conductor !33 from distortion' under heavy short circut conditions in which the terminal 91 may be accelerated by the pressure generated by the blast action of the are extinguishing material 95 faster than the tube !25 and the Operating mechanism associated therewith. The flexible conductor !33 and the sheath !34 are secured at one end to a;

metallic fltting !35 that is threaded into the lower end of a contact tip !36 which in turn is threaded i on the'lower .end of the rod-like terminal 91.

formed with a'metallic ring !20, are provided.

The edges of the ring !20are Deened over an inwardly extending flange l2! of the lower line ter- The other ends of the flexible conductor !33 and sheath !34 are secured to a cable fastener !31 that, in.turn,1s secured to one end of a cable link !39.111 the form of 'a flexible copper strip. As shown, the upper end of the cable link !38 is secured by screws !39 to a contact sleeve !40 which is threaded onto the lower end' of the cartridge housing 9! and has threaded thereon the upper end of the metallic sleeveJ IS'.

I A spring seat !4! in the fonn of a metallic ring is secured to the upper end of the indicator sleeve !25 for receivirg thereagainst the lower end of a coi! compression spring !4 2. The upper end of the spring !42 reacts against the under side of the contact sleeve !40, as shown. i

Wherfthefusible and strain elements oo and '!0! blow, the red-like terminal 91 is released. since the spring !42 is no longer restrained, it expands and moves the indicator tube !25 downwardly carrying with it the pulley !32 over which the flexible conductor !33 is looped to the position shown in Figure 10 of the drawings. Since one end of the cable link !38 is stationarily secured with respect to the rod-iike terminal 91 and the pulley !32, the former is moved downwardiy at twice the speed of the latter and, consequently, for a given extension of the spring !42 a movement of the red-like terminal 91 takes` place which is twice the extension of the spring The indicator tube !25 is a-rranged to move out 'of the lower end of the housing so as to indie V `|4!. When the flange !43 engages the upper end I oi the Iemle III, further outward movement o! the indicator tube I!! is prevented.

It will be observcd that considerable space !45 is provided between the pulley !32 and the base m at the lower end ot the indicator tube m.

This is provided ior receiving the fiexihle conducwr III in the event that the blast resulting !rom the interruption of the circuit on blowing e oi the fusible and strain elements i and in! is sumcient to drive the red-like terminal 91 downwardly at a speed which is greater than the speed ill are provided to interconnect the rod-like terminel s and the lower cartridge terminal ill; while the former is moving under the influence of the coil compression spring !42 to interrupt the circuit. Whilethe devioe is performing its` normal current carrying function it is desrable to provide a good conducting circuit between the !od-like terminal !1 and the lower Cartridge terminal IIB. For this, purpose contact 'flngers ill' are provided on the contact sleeve uu. Preferably they are integrally Iormed with the contact sleeve lili. The lower ends of the contact fingers I" are biased inwardly by a garter spring IIB to contact engagement with a cylindricai surface Me on the contact tip III. The cylindrical surface n is provided so as to permit the garter spring MI to react radially only with respect to the contact tip I!! and the rod-like terminal 31. The-cylindrical contact surface !49 permits some variation in the relative positions of the red-like terminal !1 and the contact fingers m, so that it' is unnecessary to accurately position them iongitudinally.

After the iusibleand strain elements oo and I!! have blown, it is necessary to replace the fuse cartrldge !2. In order to do this, the cap i is removed from the extension os of the upper line terminal u and the clamp nut m is unscrewed !rom the lower line terminal II. On turning the housing !il up end down, the condenser assembly l" and the ca'tridge` !2 will drop out. These steps are reversed in re-tusing 'the devioe.

In Figure of the drawing& the blown condition of the !use cartridge !I is illustrated. As there shown. the flange I on the spring seat ill abutsthe upper end u of the ferrule Ils and therehy prevents further downward movement of the Operating mechanism. The contact tip m on the lower'end bf the :od-like terminal a en- Bazes the pull y Il! and thereby its furtherdownward moven t s prevented. As previously indicated, itls desh-able to provide a'lower flashover distance within the !use cartridge !2 than outside o! the same so that it an are should be tormed nite:- the devioe has interrupted the. circuit and is in the' .condition shown in figure 10. lt'wfll be !oned within the bore ll rather than exteriorly ther-ect. such an are might be formed'as a result o! switching sur-ses or lightning strokes.

In order to insure that any subsequent' arc will be Iormed within the bore I'. the' rod-like ter- !ninni ll is 'made o! such length and the other 'puts of the devioe are so proportloned that the distance indicated at A between the upper end Iusibie and strain elements mu and III! and the contact plug IOI will be less than the distance indicated at B between the lower end of the cartridge terminal 89 and the upper end oi the metallic sleeve lili. Of course, the distance indicated at A is considerably less than the distance between the line terminals 83 and 84 at the ends of the tubular housing 80 in which' the replaceable fuse cartridge 92 is inserted.

If an arc is subsequently iormed, as described, in the bore 95 an arc extinguishing medium will be evolved from the arc extinguishing material 95 due "to the heat of the are which will tend to sweep it out of the bore 98 and extinguish the same. e

Since certain further changes can be made in the foregoing constructions'and different embodi- 'ments of the invention can be made without departing from the scope thcreo, it is intended that ali matter shown in the accompanying drawings and described hereinbeiore shall be interpreted as illustrative and not in a limiting sense.

What is claimed as new is:

1. Circuit interrupting apparatus comprising,

in combination, hlast action are extinguishlng means, a normally closed metal chamber adapted to receive the blast from said means, and racionable valve means for automatically venting said chamber on generation oi predetermined pressure therein and thereafter reclosing said chamher.

2. Circuit interrupting apparatus comprising, in combination, an insulating housing having terminals one of which includes an extension forming a normally closed chamber, blast action are extinguishing means within said housing adapted to discharge into said chamber, and valve means adapted to be opened on generation 'oi predetermined pressure within said. chamber !or venting the same and to be. closed when the pressure is relieved. I

3. Circuit nterrupting apparatus comprising, in combination, a tubular insulating housing having terminals at its ends one of which includes an extension !orming a normally closed chamber, a replaceable cartridge insertable through said chamher and' said one terminal into said housing and comprisng a blast action arc extinguishing devioe !or interconnecting said terminals and adapted to disharge into said chamber, and valve means adapted to be opened on generation of predetermined pressure within said chamber !or venting the same and to be closed when the pressure is relieved.

4. In circuit interrupting apparatus, in com-` binati on, a tub'ular !use housing, line terminl at the ends ot said ruse housing, contact !intel-s extending from one or said line terminals; and

- a replaceable cartridge insertable through the end oi said ruse housing where. the other line terminal is located including an insulating housing having a cartridge terminal at one end disposed to engage said other line terminal, a movable terminal connected to .said cattridle terminal by fusible means,` a metallic housing at the other end 'ot said insulating housing connected to said movable terminal and -wdapted to he engaged by said contact nngers, Operating machsnism within said metallic housing !or withdrwing said movable terminal !rom said cartridge terminal on blowing oi said .tusible means, and

means movable endwise out ot said !use housing in response to the'releae o! said movable. terminal tor indicating that the Iusbe means hu s. In circuit interrupting apparatus. in combination, a tubular !use housing, line terminals at other line terminahand an indicator movable endwise out or said metallic sleeve in response to the release of said movable terminal for indicating that the fusible means has blown.

6. `In a circuit interrupter, in combination, an insulating housing having means therein providing a longitudinal bore, a terminal at one end of said housing, a rod-like terminal movable in said bore, fusible means interconnecting said terminals and restraining movement of the latter, a metallic sleeve connected to said red-like terminal and secured to the other end of said housing and constituting a terminal therefor, pulley support means movably mounted within-said metallic sleeve anda pulley carried thereby, flexible means loped over said pulley and having one end secured to said rod-like terminal and the other. end stationarily secured with respect to said rod-like terminal and pulley, and spring tending t-rom one of said line terminals inwardly 4 of said housing toward its other end'. and a. replaceable fuse cartridge having terminals at its ends and insertable through said other end of said housing to position its terminals respectively in engagement with said conductor means and the other line terminal.

10. Circuit interrupting apparatus comprising, in combination, a tubular fuse housing having ring-like line terminals at its ends, a tubular metallic sleeve extending from one of said ring-'like' line terminals inwardly of said housing toward its other end, and a replaceable fuse cartridge having terminals at its 'ends and insertable through said other end of saidhousing and the ring-like terminal thereat to position its terminals respectively in engagement with said metallic means biasing said pulley support means whereby said rod-like terminal the latter is moved at twice thespeed of said pulley support means, said pulley support means being adapted to move out of said metallic sleeve to indicate that the fusible ing a longitudinal bore, a terminal at one end of said housing', a rod-like terminal movable in said bore, fusible means' interconnecting said terminals and restraining movement of the latter, a metallic sleeve connected to' said rod-like terminal and secured to the other end of said housing' and constituting a terminal thereior, spring means within said metallic sleeve for withdrawing said rod-like terminal when said fusible means blows, and an indicator movable endwise out of said metallicsleeve in response' to the release of said movable terminal for indicating that the fusible means has blown, said indicator being arranged and adapted to substantially close said metaliic sleeve whereby entrance of extraneous matter in to the circuit interrupter is prevented.

8. Circuit interruptirig apparatus comprising.

, in combination, a tubular fuse housing having X line terminals at 'its ends; and a replaceabl use .cartridge insertable through one end of said housing and included a cartridge terminal disposed to engage'one of said line terminals, a mass of solid arc extinguishing material having athore extending longitudinally therethrough, a red-like terminal in said bore, spring means biasing said red-like terminal for movement toward the other line terminal, fusible means interconnecting said cartridge and -rod-like terminal and' restraining the latter from movement under the influence of said spring means, and flexibie conductor means interconnecting said rod-like and other line terminal and extending out of the other end of said fuse housing.

9. Circuit interrupting apparatus` comprising, in combination, a tubular fuse housing having line terminals at its ends, conductor means ex- "on blowing of said' fusible means and release of sleeve and the last mentioned ring-like terminal.

11. Circuit interrupting apparatus comprlsing, in combination, a tubular fuse housing having line terminals at its ends, conductor means extending from one of said line terminals inwardly of said housing toward its other end; and a replaceable !use cartridge insertable through said other end of said housing including a cartridge terminal disposed to engage the line terminal at said one end of said fuse housing, a mass of solid are extinguishing material having a bore extending longitudinally therethrough, a red-like terminal in said bore biased for movement relative thereto away from said cartridge terminal, fusible means intercnnecting said cartridge and rod-like terminals and restraining the latter, and a second cartridge terminal connected to and movable with said rod-like terminal and disposedmlnals, a red-like terminal in said bore biased for movement relative thereto away from said cartridge terminal, fusible means interconnecting said cartridge and rod-iike terminals and restraining the latter, and a second cartridge terminal connected to and movable with said rodlike terminal and disposecl to engage the other of said line terminals. I

' 13. Circuit interrupting apparatus comprlsing, in combination, a tubular fuse housing having ring-like line terminals at'iis ends, a tubular metallic sleeve extending from one of said ring-like line terminals inwardly of said housing toward its other end; and a replaceable fuse cartridge insertable through said other end of said housing ,and the ring-like terminal thereat including a cartridge terminal disposed to engage the ringlike terminal at said other end of said housing,

a mass of 'solid arc extinguishing material having a bore extending longitudinally therethrough, a rod-like terminal in said bore biased for movement relative thereto away from said cartridge terminal, fusible means interconnecting said cartridge and rod-like terminals and restraining the latter, and a second cartridge terminal connected to and movable with said red-like terminal and disposed to engage said tubular metaliic sleeve.

14. Circuit interrupting apparatus comprlsing, in combination, a tubular fuse housing havin line terminals at its ends, conductor means extending from one of said line terminals inwardly of said housing toward its other end'; and a rearc extinguishing material having a bore extend- I ing longitudinally therethrough, a rod-like terminal in said bore biased !or movement relative thei-eto away from said cartridge terminal, !usible means interconnecting said cartridge and rodlike terminals and restraining the latter, a second 10 cartridge terminal' connected to and movable with i said red-like terminal and disposed to engage said conductor means, and flexible conductor means interconnecting said rod-like 'terminal and said one line terminal to maintain a good conll ducting circuit therebetween after said rod-like and second cartridge terminals are released !or movement on blowing oi said iusible means.

15. A replaceable i'use cartridge for insertlon in a !use housing having a pair ot line terminals oomprising, in combination, an insulating sleeve containing a mass of solid arc extinguishing material having a, bore extending longitudinally therethrough, a cartridge terminal at one end of said sleeve adapted to engage one o! said line terminals, a red-like terminal in said bore blased for movement relative thereto away from said cartridge terminal, !usible means interconnecting, said cartridge and rod-like termlnals and restraining the latter, a second cartridge terminal 80 connected to and movable with said rod-like terminal and disposed to engage the other of said line terminals, and flexible conductor means connected to said rod-like terminal and adapted to be connected to said other line terminal to maintain a good conducting circuit therebetween after said rod-like and second cartridge termlnals are' released for movement on blowing of said iusible means.

.s. In circuit interrupting apparatus, in com- 0 bination, a tubular !use housing, line terminals at the ends oi' said !use housing, contact nnge-s extending from one of said line terminals; and a replaceable cartridge insertable through the end o! said !use housing where the other line terminal is located including an insulating housing having a cartridge terminal at one end disposed to engage said other line terminal. a movable terminal connected to said cartridge terminal by fusible means, a metallic housing at the other end of said insulating housingconnected to said movable terminal and adapted to be engaged by 'said contact flngers, and operating mechanism within said metallic housing for withdrawing said movable terminal from said cartridge terminal on v blowing of said !usible means.

17. In circuit internpting apparatus, in comblnation, a. tubular !use housing. line terminals at the ends oi' said !use housing, a metallic sleeve extending inwardly oi said !use housing !rom one 00 of said line terminals having resilient contact !1ngers biased radially inwardly thereot; and a replaceable cartridge insertable through the end o! said !use housing where the other line terminal is located including m insulating housing ham a cartridge termina'at one end disposed to enggesidothe'lineterminaLamovableterminal' connectedtosaidcartridgete-minalbyiusible means, ametalllc housing telecoped with the otherendoisaidinsulatinghousingandconnected to and movable with said movable terminalawayfromsaidcartridgeterminaland" adaptedtobeengagedbysaid contactflngeraand Operating mechanism within said metallic houssaid cartridge terminal on blowing oi said iusible means.

18. In circuit interrupting apparatus, in combination, a tubular !use housing, line terminals at the ends oi said ruse housing, a metalllc sleeve extendlng inwardly of said ruse housing from one oi' said line terminals having resilient contact iingers biased radially inwardly thereoi; and a replacea'ble cartridge insertable through the end of said !use housing where the other line terminal is located including an insulating housing having a cartridge terminal at one end disposed to engage said other line terminal, a movable terminal connected to said cartridge terminal by fusible means, a metallic housing telescoped with the other end of said insulating housing and connected to and movable with said movable terminal away from said Cartridge ter- -minal and adapted to be engaged by said contact nngers, Operating mechanism within said metallic housing for withdrawing said movable terminal from said cartridge terminal on blowing of said fusible means, and means preventing relative rotary movement between said metalllp housing and said insulating housing as long as said fusible means remains intact.

19. In circuit interrupting apparatus, in combination, a tubular fuse housing, line terminal! at the ends ol said !use housing, contact flngers extending from one of said line terminals; a replaceable cartridge insertable through the end of said !use housing where the other line terminal is located including an insulating housing having a cartridge terminal at one end disposed to engage 'said other line terminal, a movable terminal connected to said cartridge terminal by i'usible means, a metaliic housing at the other end oi said insulating housing connected to said movable terminal and adapted to be engaged by i said contact flngers, and Operating mechanism within said metallic housing for withdrawing said movable terminal from said cartridge terminal on blowing of said tuslble means; and clamp means cooperating with said contact fingers for holding the same in intimate contact engagement withsaid metallic housing.

20. In circuit interrupting apparatus, in combination,. a tubular i'use housing, line terminals a metallic sleeve secured to the other end ot said insulating housing and connected to said e movable terminal and disposed to engage said contact ilngers; said cartridge terminal beim adapted to always engage said one line terminal I in the same relative position while the position oi said metallic sleeve with respect to said contact flngers is variable, and clamp means cooperating with said contact flngers for urging the same radially inwardly and holding them in intimate contact engagement with said metallic sleeve.

21. In circuit interrupting apparatus, in combination. a tubular !use housing, line terminals at the ends of said !use housing, circulariy disposed contact i'ingers extending !rom one of said line terminals: a replaceable cartridge insertable through one end of said i'use housing including an insulating housing having a cartridge ingIo-withdrawingaidmovabetermmtmm 'llterninlatoneenddsposedtoengageoneline terminal, a movable terminal connected to said cartridge terminal by msible means, a metallic seeve Secured to the other end of said insulating housing and connected to said movable terminal and disposed to engage said contact flngers and flngers is variable, and clamp means cooperating with said contact flngers for urging the same radially inwardlx and holding them in intimate contact engagement with said metallic seeve.

r 22. In acircuit interrupter, in combination, an

I insuiating housing having means therein prpviding a longitudinalbore, a terminal at one end of said housing, a rod-iike terminal movable in said bore, usible means interconnecting said terminals and restraining movement 'of the latter, pulley support means and a pulley carried th'ereby, guide means for said pulley support means, spring means biasing said pulley support means away from said insulating housing, and fiexble means looped over said pulley with one end secured to said rod-lke terminal and the other end stationariiy secured'with respect to said red-like terminal and pulley, there being space provided beyond said pulley in the direction of its movement for receiying said flexible means in the event that the same is driven past said pulley.

23. In a circuitinterrupter, in combination, an insulating housing having means therein providing a longitudinal'bore, a terminal at one end of said housing, a red-like terminal movabe in said bore, fusible means interconnecting said terminals and restraining movement ot the latter, pulley support means and a pulley carr'ied thereby, guide means for said pulley support means, spring means biasing said pulley support ductor ormed ot a .plurality oi sti-ami of wire ooped over said pulley and secured at one end to said red-like terminal, and a metallic strip secured at one end to the other end of said flexible conductor and stationarily secured at its other end with respect to said red-like terminal and pulley.

24. In a circuit interrupter, incombination, an insuiating housing Having means therein providing a lonsitudinai bore, a terminal at one end of said housinma red-like terminal movable in said bore, fusible means interconnecting said terend secured to said !od-like terminal and the ga other end stationarily secured with respect to said red-like terminal and puiley, and-a flexible metallic sheath surrounding said fiexibe conductor ior protecting the same.

25. In a' circuit interrupter, in combination, an insulating housing having means therin providing a longitudinal bore, a terminal at one end of. said housing, a'rod-like terminal movable in said bore, usible means interconnecting said ter minals and restraining movement or the letter, pulley support means and -a pulley carried thereby. uide means Ior` means, spring means biasing said pulley support mean away from said insulating housing, a coni said red-like terminaL'a flexible metalli ,sheath means away from said insulating housing, a conu surrounding said conductor'tor protecting the same, and`a metaliic stripxsecured -at one end to the other end o! said flexible conductor and stationariy seem-ed at its other end with respect' to said :od-like termin al and pu y. i-

I i noon a 'rsrPLt'-r.

said pulley support e 

